The proposal represents the initial step in a project which has as its objective an examination of the relationship between the nature of internal migration and the level of social-economic development of the country in which it is taking place. Within this context, the proposal seeks to explore more intensively recent census data for the United States and one or more other countries, by utilizing available public use computer tapes. It will build on preliminary analysis of published material for the United States in 1970, which indicates that most interstate migrants are moving for at least the second time and that those who are going to a third state of residence are a highly selected group, differing sharply from those who return to thir home state, and, also, though less sharply, from those who are leaving the home state. Following through on this, we will test whether these distinctions remain if "pre-migration" status is examined (U.S. 1970), if time trends are examined (U.S. 1960), and if countries who have not moved so far along on the continuum of "development" are examined.